WASHINGTON — The outcome in Iowa was both electorally inconclusive and politically clarifying. There is a Republican Party, supporting Mitt Romney, that wants to win an election. And there is a Republican Party, supporting Ron Paul, that wants to make a point about limited government.

This division is not entirely ideological. There are rock-ribbed conservatives who believe that the highest political priority is the early retirement of Barack Obama. There are evangelicals — uncomfortable with libertarianism and the foreign policy of Charles Lindbergh — who have nevertheless joined Paul's protest against swollen government.

Based on recent history, the party of electability will eventually prevail. Activists rooting for the new (and more extreme) Barry Goldwater will need to explain how he avoids the political fate of the first one.

But perhaps the most surprising result of the Iowa caucuses was the return of compassionate conservatism from the margins of the Republican stage to its center. Rick Santorum is not only an outspoken social conservative; he is the Republican candidate who addresses the struggles of blue-collar workers and the need for greater economic mobility. He talks not only of the rights of the individual but of the health of social institutions, particularly the family. He draws out the public consequences of a belief in human dignity — a pro-life view applied to the unborn and to victims of AIDS in Africa.

Electability Republicans can live with Santorum's populism and moralism. Anti-government activists cannot, and have begun their assault. Santorum is referred to as a "pro-life statist." David Boaz of the Cato Institute cites evidence implicating him in shocking ideological crimes, such as "promotion of prison ministries" and wanting to "expand colon cancer screenings for Medicare beneficiaries."

But Santorum is not engaged in heresy; he represents an alternative tradition of conservative political philosophy. Libertarians may wish to claim exclusive marketing rights, but there are two healthy, intellectual movements in American conservatism: libertarianism and religious (particularly Catholic) social thought.

Libertarianism is an extreme form of individualism, in which personal rights trump every other social goal and institution. It is actually a species of classical liberalism, not conservatism — more directly traceable to John Stuart Mill than Edmund Burke or Alexis de Tocqueville. The Catholic (and increasingly Protestant) approach to social ethics asserts that liberty is made possible by strong social institutions — families, communities, congregations — that prepare human beings for the exercise of liberty by teaching self-restraint, compassion and concern for the public good. Oppressive, overreaching government undermines these value-shaping institutions. Responsible government can empower them — say, with a child tax credit, or a deduction for charitable giving — as well as defend them against the aggressions of extreme poverty or against "free markets" in drugs or obscenity.

This is not statism; it is called subsidiarity. In this view, needs are best served by institutions closest to individuals. But when those institutions require help or protection, higher order institutions should intervene. So when state governments imposed Jim Crow laws, the federal government had a duty to overturn them. When a community is caught in endless economic depression and drained of social capital, government should find creative ways to empower individuals and charities — maybe even prison ministries that change lives from the inside out.

This is not "big government" conservatism. It is a form of limited government less radical and simplistic than the libertarian account. A compassionate conservative approach to governing would result in a different and smaller federal role — using free-market ideas to strengthen families and communities, rather than constructing centralized bureaucracies. It rejects, however, a utopian belief in unfettered markets that would dramatically increase the sum of suffering.

In a 2005 speech at the Heritage Foundation, Santorum argued that men and women should not be treated either as "pathetic dependents" or as "radical individuals." "Someone," he argued, "always gets hurt when masses of individuals do what is only in their own self-interest. That is the great lie of liberal freedom. ... Freedom is liberty coupled with responsibility to something bigger or higher than the self. It is a self-less freedom. It is sacrificial freedom. It is the pursuit of our dreams with an eye towards the common good."

Santorum is far from a perfect candidate. His nomination is unlikely. But his success should not really surprise. Every four years, Republicans eventually realize that they need a hopeful domestic policy agenda — some vision of the common good — that appeals beyond their base. If Santorum does not win the nomination, the winner would be wise to listen to him.